ref_transaction_update(): remove "have_old" parameter

Instead, verify the reference's old value if and only if old_sha1 is
non-NULL.

ref_transaction_delete() will get the same treatment in a moment.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

branch.c

@@ -284,8 +284,9 @@ void create_branch(const char *head,
 
 		transaction = ref_transaction_begin(&err);
 		if (!transaction ||
-		    ref_transaction_update(transaction, ref.buf, sha1,
-					   null_sha1, 0, !forcing, msg, &err) ||
+		    ref_transaction_update(transaction, ref.buf,
+					   sha1, forcing ? NULL : null_sha1,
+					   0, msg, &err) ||
 		    ref_transaction_commit(transaction, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);

builtin/commit.c

@@ -1767,7 +1767,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	    ref_transaction_update(transaction, "HEAD", sha1,
 				   current_head
 				   ? current_head->object.sha1 : NULL,
-				   0, !!current_head, sb.buf, &err) ||
+				   0, sb.buf, &err) ||
 	    ref_transaction_commit(transaction, &err)) {
 		rollback_index_files();
 		die("%s", err.buf);

builtin/fetch.c

@@ -416,8 +416,10 @@ static int s_update_ref(const char *action,
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
-	    ref_transaction_update(transaction, ref->name, ref->new_sha1,
-				   ref->old_sha1, 0, check_old, msg, &err))
+	    ref_transaction_update(transaction, ref->name,
+				   ref->new_sha1,
+				   check_old ? ref->old_sha1 : NULL,
+				   0, msg, &err))
 		goto fail;
 
 	ret = ref_transaction_commit(transaction, &err);

builtin/receive-pack.c

@@ -971,7 +971,7 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		if (ref_transaction_update(transaction,
 					   namespaced_name,
 					   new_sha1, old_sha1,
-					   0, 1, "push",
+					   0, "push",
 					   &err)) {
 			rp_error("%s", err.buf);
 			strbuf_release(&err);

builtin/replace.c

@@ -172,7 +172,7 @@ static int replace_object_sha1(const char *object_ref,
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, ref, repl, prev,
-				   0, 1, NULL, &err) ||
+				   0, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
 

builtin/tag.c

@@ -733,7 +733,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, ref.buf, object, prev,
-				   0, 1, NULL, &err) ||
+				   0, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
 	ref_transaction_free(transaction);

builtin/update-ref.c

@@ -198,8 +198,9 @@ static const char *parse_cmd_update(struct ref_transaction *transaction,
 	if (*next != line_termination)
 		die("update %s: extra input: %s", refname, next);
 
-	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-				   update_flags, have_old, msg, &err))
+	if (ref_transaction_update(transaction, refname,
+				   new_sha1, have_old ? old_sha1 : NULL,
+				   update_flags, msg, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;
@@ -297,7 +298,7 @@ static const char *parse_cmd_verify(struct ref_transaction *transaction,
 		die("verify %s: extra input: %s", refname, next);
 
 	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-				   update_flags, 1, msg, &err))
+				   update_flags, msg, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;

fast-import.c

@@ -1716,7 +1716,7 @@ static int update_branch(struct branch *b)
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, b->name, b->sha1, old_sha1,
-				   0, 1, msg, &err) ||
+				   0, msg, &err) ||
 	    ref_transaction_commit(transaction, &err)) {
 		ref_transaction_free(transaction);
 		error("%s", err.buf);
@@ -1756,8 +1756,8 @@ static void dump_tags(void)
 		strbuf_reset(&ref_name);
 		strbuf_addf(&ref_name, "refs/tags/%s", t->name);
 
-		if (ref_transaction_update(transaction, ref_name.buf, t->sha1,
-					   NULL, 0, 0, msg, &err)) {
+		if (ref_transaction_update(transaction, ref_name.buf,
+					   t->sha1, NULL, 0, msg, &err)) {
 			failure |= error("%s", err.buf);
 			goto cleanup;
 		}

refs.c

@@ -3654,7 +3654,7 @@ int ref_transaction_update(struct ref_transaction *transaction,
 			   const char *refname,
 			   const unsigned char *new_sha1,
 			   const unsigned char *old_sha1,
-			   unsigned int flags, int have_old, const char *msg,
+			   unsigned int flags, const char *msg,
 			   struct strbuf *err)
 {
 	struct ref_update *update;
@@ -3664,9 +3664,6 @@ int ref_transaction_update(struct ref_transaction *transaction,
 	if (transaction->state != REF_TRANSACTION_OPEN)
 		die("BUG: update called for transaction that is not open");
 
-	if (have_old && !old_sha1)
-		die("BUG: have_old is true but old_sha1 is NULL");
-
 	if (!is_null_sha1(new_sha1) &&
 	    check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
 		strbuf_addf(err, "refusing to update ref with bad name %s",
@@ -3676,7 +3673,7 @@ int ref_transaction_update(struct ref_transaction *transaction,
 
 	update = add_update(transaction, refname);
 	hashcpy(update->new_sha1, new_sha1);
-	if (have_old) {
+	if (old_sha1) {
 		hashcpy(update->old_sha1, old_sha1);
 		flags |= REF_HAVE_OLD;
 	}
@@ -3693,7 +3690,7 @@ int ref_transaction_create(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
 	return ref_transaction_update(transaction, refname, new_sha1,
-				      null_sha1, flags, 1, msg, err);
+				      null_sha1, flags, msg, err);
 }
 
 int ref_transaction_delete(struct ref_transaction *transaction,
@@ -3702,8 +3699,9 @@ int ref_transaction_delete(struct ref_transaction *transaction,
 			   unsigned int flags, int have_old, const char *msg,
 			   struct strbuf *err)
 {
-	return ref_transaction_update(transaction, refname, null_sha1,
-				      old_sha1, flags, have_old, msg, err);
+	return ref_transaction_update(transaction, refname,
+				      null_sha1, have_old ? old_sha1 : NULL,
+				      flags, msg, err);
 }
 
 int update_ref(const char *action, const char *refname,
@@ -3715,8 +3713,8 @@ int update_ref(const char *action, const char *refname,
 
 	t = ref_transaction_begin(&err);
 	if (!t ||
-	    ref_transaction_update(t, refname, sha1, oldval, flags,
-				   !!oldval, action, &err) ||
+	    ref_transaction_update(t, refname, sha1, oldval,
+				   flags, action, &err) ||
 	    ref_transaction_commit(t, &err)) {
 		const char *str = "update_ref failed for ref '%s': %s";
 

refs.h

@@ -265,8 +265,8 @@ struct ref_transaction *ref_transaction_begin(struct strbuf *err);
 /*
  * Add a reference update to transaction.  new_sha1 is the value that
  * the reference should have after the update, or null_sha1 if it should
- * be deleted.  If have_old is true, then old_sha1 holds the value
- * that the reference should have had before the update, or zeros if
+ * be deleted.  If old_sha1 is non-NULL, then it is the value
+ * that the reference should have had before the update, or null_sha1 if
  * it must not have existed beforehand.
  * Function returns 0 on success and non-zero on failure. A failure to update
  * means that the transaction as a whole has failed and will need to be
@@ -276,7 +276,7 @@ int ref_transaction_update(struct ref_transaction *transaction,
 			   const char *refname,
 			   const unsigned char *new_sha1,
 			   const unsigned char *old_sha1,
-			   unsigned int flags, int have_old, const char *msg,
+			   unsigned int flags, const char *msg,
 			   struct strbuf *err);
 
 /*

sequencer.c

@@ -252,7 +252,7 @@ static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 	if (!transaction ||
 	    ref_transaction_update(transaction, "HEAD",
 				   to, unborn ? null_sha1 : from,
-				   0, 1, sb.buf, &err) ||
+				   0, sb.buf, &err) ||
 	    ref_transaction_commit(transaction, &err)) {
 		ref_transaction_free(transaction);
 		error("%s", err.buf);

walker.c

@@ -299,7 +299,7 @@ int walker_fetch(struct walker *walker, int targets, char **target,
 		strbuf_reset(&refname);
 		strbuf_addf(&refname, "refs/%s", write_ref[i]);
 		if (ref_transaction_update(transaction, refname.buf,
-					   &sha1[20 * i], NULL, 0, 0,
+					   &sha1[20 * i], NULL, 0,
 					   msg ? msg : "fetch (unknown)",
 					   &err)) {
 			error("%s", err.buf);